Wrysgan Quarry

Overview

An underground slate quarry above Tanygrisiau, worked intermittently from the 1830s and continuously from around 1850 to 1946, remembered for the dramatic incline that carried its slate 625 feet down to the Ffestiniog Railway and for the barrack cottages that housed workers too far from home to return nightly.

History

Wrysgan was worked intermittently from the 1830s before continuous working began around 1850 under the newly formed Wrysgan Slate and Slab Quarries Co. Ltd. A processing mill was built in 1854, followed by a second, lower mill in 1865 equipped with eighteen saws, twenty dressers and two planers. An early balanced incline served the upper levels before a spectacular new incline, completed in 1872, replaced it — descending 625 feet through a tunnel to connect directly with the Ffestiniog Railway below. Because the site, at around 1,390 feet above sea level, was too remote for most workers to return home each night, barrack cottages were built in the 1870s: two rows of eleven small stone dwellings offering only basic protection from the weather. The quarry grew to work eight underground levels, reaching peak output of around 3,000 tons of finished slate in 1904 with a workforce of over 100 men. New Wrysgan Slate Quarry Ltd relaid the incline in 1923 under owner T.O. Williams, but the operation had shrunk drastically by its final years: only eleven workers produced 348 tons in 1945-46. Wrysgan closed in 1946 on the death of Williams, its last owner.

Geology

Cambrian slate of the Ffestiniog district, worked underground on eight levels rather than by open quarrying, typical of the deep-mined slate deposits around Blaenau Ffestiniog.

Workings

Underground chambers worked across eight levels, connected to two successive surface processing mills (1854 and 1865) and served first by a balanced incline, then from 1872 by a 625-foot incline down to the Ffestiniog Railway.

Closure

Closed in 1946 following the death of owner T.O. Williams, after output had fallen from a 1904 peak of around 3,000 tons a year to just 348 tons in its final full season.

What remains

The incline survives in part, though it was damaged during 1950s road construction for access to the Llyn Stwlan reservoir; most adits remain open, but all underground chambers are considered unstable and unsafe.

Abandoned workings can be dangerous — unstable ground, uncapped shafts, flooding and bad air are common even where a site looks safe from the surface. This entry describes history and general location only; it is not an access guide.

Recorded claims

Individual factual claims, each attached to the source(s) that support it below. Where sources disagree, both are kept.

• The quarry was worked intermittently from the 1830s, with continuous working beginning around 1850 under the newly formed Wrysgan Slate and Slab Quarries Co. Ltd. ¹
• A new incline completed in 1872 replaced an earlier balanced incline, descending 625 feet through a tunnel to connect directly with the Ffestiniog Railway. ¹
• The quarry reached peak output of around 3,000 tons of finished slate in 1904, with a workforce of over 100 men across eight underground levels. ¹
• By 1945-46 only eleven workers remained, producing 348 tons that year; the quarry closed in 1946 following the death of its last owner, T.O. Williams. ¹
• Because the site was too remote for most workers to return home nightly, barrack cottages were built to house them — a common practice at the isolated slate quarries of the Ffestiniog district generally. ^1,2

Images

Sources

1. (secondary) Wrysgan quarry — Wikipedia
2. (secondary) Ruins of the Anglesey Barracks, Dinorwig — History Points

Record created: 27 August 2026 · Last researched: 27 August 2026